Successively-operated tone modulators



My 22, 192s.

1,670,351 J. H. HAMMOND` JR SUCCESSIVELY OPERATED TONE MODULATORS Filed Nov. 17, 1925 5 Sheets-Sheet 1 May 22, 1928. 4

J. H. HAMMOND. JR

sUccEssIvELY OPERATED TONE MoDuLAToRs Filed Nov. 17, 1925 5 Sheets-Sheet 2 May 22, 1928.

J. H. HAMMOND, JR

SUCCESSIVELY OPERATED TONE MODULATORS Filed vNov. 17, 1925 5 Sheets-Sheet w m m w May 22,' 1928. 1,670,351

J. H. HAMMOND. JR

` SUCCESSIVELY OPERATED TONE MODULATORS l Filed Nov. 17, 1925 5 Sheets-Sheet 4 l L J l p L 1mm :r11 r1 www m May z2,` 192s.

' 1,670,351 J. H. HAMMOND. JR

SUCCESSIVELY OPERATED TONE MODULATORS Filed Nov. 17, 1925 5 Sheets-Sheet 5 Patented May 22, 1928.

UNITED STATES JOHN HAYS HAlVIlYIOND,l JR., OF GLOUCESTER, MASSACHUSETTS.

SUOCESSIVELY-OPERATED TONE.,MODULATORS.

Application filed November 17, 1925. Serial No. 69,569.

This invention relates to musical instrument of the percussive type and to improved means for producing music by percussion.

The invention has reference particularly to musical instruments of the pianoforte type and to improved control of musical sound producedy by such instruments and it is an object of the invention to provide improved means for initially controlling the least brilliant tone produced by the instrument and for subsequently controlling the more brilliant tone, thereby producing a smooth crescendo effectthroughout the intensity range. f

I have discovered that by providing a musical instrument of the percussive type Asuch as the pianoforte, with a sound insulated casing having a metal lining so as to form in combination with the sounding board two separate resonating chambers, and that by providing these chambers with movable reflecting devices varranged so that in onel position the chambers are closed effectively to suppress the sound, and so that in other positions the chambers are opened or partially opened, the sound emitted from the different chambers in different directions varies with respect to the brilliance of tone. In the case of an instrument of the grand piano type, such as will be illustrated in the present disclosure, it has been found that the least brilliant tone is emitted from the lower resonating chamber and that a relatively greater brilliance of tone is obtained from the upper resonating chamber, and that by separately controlling the sound emitted fromy these chambers, a very gradual crescendo and diminuendo can be obtained. It. is an object of the present invention to provide means for producing such gradual changes in tone.

I have also discovered that when two groups of refiecting devices are positioned above and below the strings respectively as described, a given amountr of opening for emission of sound of the two groups of re- 'fiectorsresults in less tone volume being produced from the lower reso-nating chamber than from the upper one. the. ratio being in the proportion ofV 6 and 8 approximately, and it is a further object of the invention to provide means for controlling the groups of reflectors successively so as to produce a very delicate shading of tone and so that the operation of controlling the tone volume from minimum to maximum can be greatly prolonged, thus increasing the varieties of expression impartedy to the music.

It has also been found that smooth control of tone volume through relatively small apertures is much more difficult than through large apertures, inasmuch as a large change of tone is produced with small change of' opening, and onev of the features of the present invention relates to the initial control of the group of reflectors through which the smaller volume of tone is emitted and thus providing a more gradual increment.

Other objects will appear` from the following description taken in connection with the accompanying drawings in which:

Figure 1 is a top plan view of so much of a grand piano having features of the invention applied thereto, as is necessary to an understanding of the invention;

Figure 2 is a front elevation partly in section of the piano shown in Figure 1.

Figure 3 is a detailed cross section taken on the line 3-3 ofFigure 1.

Figure et is a bottom plan View of a portion of the mechanism shown in Figure 2.

Figure 5 is a bottom plan view of a modified formy of the invention.

Figure 6 is a fragmentary front elevation of a part of the mechanism shown in Figure 5.V

Figure 7 is a top plan view partly in section of the piano shown in Figure 5.

Figure 8 is a fragmentary top plan View of another modified form of the invention.

Figure 9 is a bottom plan View of the piano shown in Figure 8.

Figure 1() is a diagrammatic view of part of the mechanism shown in Figure 9.

Figure 11 shows a modified detail as applied to the mechanism shown in Figures 8 and 9.

Figure 12 is a diagram showing the variation of the volume of sound emitted by the tone modulators shown. in Figures 1 and 2.

Figure 13 is a diagram showing the volume of sound emitted by the tone modulators shown in Figures 8 and 9.

Figure 14 is a diagram showing the volume of sound emitted by these tone modulators when the adjusting device shown in Figure 11 is used.

Like ,reference characters refer to like parts in the several figures of the drawings.

In the following description and claims parts will be identified by specific names for Convenience of expression but they are intended to be as generic as their application to similar parts or equivalent constructions as the art will permit.

Referring to Figures 1 to 4 inclusive, of the drawings. the invention is shown as applied to a grand piano .including la casing 10. For producing musical sound there is provided within the casing a plurality of tuned strings such as 11, tuned to the notes of the musical scale. It will be understood that there may be provided for each note of the musical scale, one or more of such strings, as may be desired. For eX- ample, in the lower part of the scale asingle string may be employed ,for each note; in

. the upper part of the scale three strings may be employed 'for each note;4 and in an intermediate part et' the scale two strings may beemployed for. each note. The strings y11 are mounted ina usualtrame 12 in a conventional manner.l For vibrating the strings `for each of the notes of the scale by percussion there is provided a. suitable hammer action such as 13 operatively connected to one key 1.4 ot the manual ot the piano. A soundingboard 15 is provided within the casing 10. A pedal block 16 is carried at the lowerend of two upright bars 17 Vand 18 depending trom the bracket 19 secured to the casing otthe pia-no below the manual. A plurality of pedals shown threein number as at 21, 22 and 23 is positioned on the pedal block V16, the two right hand pedals 22 and 23 as seen in Figure 2 being connected to the sustenuto and loud pedal action of the piano in a; conventional manner, and having no bearing on the present invention need not be further described.

The left hand pedal 21 is operatively connected ,to a vertical reciprocating rod.24,

, slidably mounted in the bracket 19, and engages at its upper endone arm of a bell crank lever 25.v The bell crank lever 25 is pivotally mounted on a pivot .pin 26 secured to the bracket 19 and is Vengaged by a. leaf spring 27 secured to the `casing of the piano whereby the pedal 21 and associated parts are normally, but yieldingly maintained in the position illustrated in li`igure 2. The

p opposite arm of the bell crank lever 25 is connected to one end of a link 28, the other end of which is pivotally connected to an arm 29 which is rigidly secured to a vertical rotatable shaft 31. This shaft is mounted in spaced bearings such as 32 and 33, secured respectively to portions ot the piano casing 16. There is provided on the shaft 31a collar, 34 rigidly secured thereto for preventing the shaft 31 from longitudinal displacement with respect toits bearings.

An arm 35 is atlixed to the shaft 31 below the lower wall ot the casing- '10 and is pivotally connected at its outer end, as clearly shown in Figure 4, to a link 36 which is connected to a reciprocating connecting rod 37. The rod 37 is pivotally connected at spaced points with a plurality of arms 38 each of which is mounted upon oneof the tone reflectors forming the lower group, and which will be more tullv described hereinafter. The. rodv 37 is formed ot a material which isV slightly flexible being sufficiently yielding to permit movement of the parts connected thereto. I have tound that a ,rod formed of a material such as brass approximately threesixteenth inches in diameter is sufficiently yielding for the purpose.

There isr secured to the shatt 31 near the upper wall of the casing 10 an armv 41, relatively longer than the arm 35.'the outer end of which is pivotallyconnected toa connecting link 42. VThe other end of Vthe link 42 is heldbetween a pair of spaced rollers 43 (see Figure 3), which are mounted in a bracket 44 rigidly Vsecured to a reciprocating connecting rod 45. The rod 45 is formed of a material similar vtorthat of the lower connecting rod 37.v rFwo collars 46 and 47 are adjustedly secured to the rod 42. As clearly shown in Figure 1. oneor" the collars 46 is so positioned on the rod'42 as to maintain a compression spring 48 in position on the rod 42 between the collar 46 and the bracket- 44,`there being provided a suitable washer 49 vagainst the face of Vthe bracket 44.to serve as an abutment tor the spring 48. The reciprocating rod 45 is similar tothe lower reciprocating rod 37 and is pivotally connected at spaced points with a plurality ot arms 51 each of which is mounted on one of the sound wave reflectors such as'52 forming the upper vgroup of sound wave reflectors. y.

The casing 10 ot the piano is provided with oppositely disposed 'controllable apertures as at 60. 61. (see Figure 2l. and the boundary walls intermediate to these apertures may be constructed to include a layer ot substantially sound 'insulating material. The interior face of the boundary walls of the casing is also providedv with a layer 62 ot sound reflecting' material, such as sheet aluminum. The upper group of reflectors 52 are each pivotally mounted o-n their longitudinal axes in the upper aperture of the casing serving` to control the emission ot sound in 4ageneral Vupward direction. Each reflector 52 is preterablyinthe form of an elongated member having beveled edges and pivotally mounted to rotate about its longitudinal axis (see Figure 2). Each reflector is provided on its inner surfacer with a layer 63 of sound reilecting material which may be ot sheet metal having a smooth sur- Y face such as sheet aluminum.

ln the lower aperture 61 ot the casing. there is mounted the lower groupl of reflectors to control` the emission of sound. The construction ot the lower group of relectors corresponds to that of the upper nero-,351

group and includes for eachl reflector a sound reflecting layer on the inner face, which in this' instance ifs the upperA surface. Surrounding each of theV apertures the casing includes an upper wall 64 and a lower wall 65 skirting therespective apertures, and having the edge beveled to conform to the edge of the contiguous reflector and having on the inner face a layer of sound reflecting material such as has been described with respect to the remainder of the casing.

' There are thus formed two resonating chambers, onel designated by the reference character 66 (see Figure 2) and extending between the upper series of reflectors and the sounding board 15, and a second resonatingchamber designated 67 extending between the sounding board* and the lower series of reflectors.

InA the operation of the form of invention shown in Figures 1 to 4 inclusive, when the pedal 21 is depressed by the performer the vertical rod 24 is raised thereby rotating the belli crank lever 25 in a coun-ter clockwise direction as seen in F igure 2, against the tens-ion of the retractile spring 27. This movement is communicated to the link 28 and thereby to the shaft 31 which is rotated in a counter clockwise direction as seen in Figure 4. The two different-ly characterized arms 35 and 41 secured to the shaft 31, are moved in a similar direction, and this motion is communicated to the link 36` and the rod 42, causing thelnto be' moved towards the right ofthe Figures 1 and 2. As the arm 41 is relatively longer than the arm 35, the upper tone reflectors 45 controlled by the arm 41 will be closed first. The arrangenient is such that when the pedal 21 has been depressed sufli'ciently to close fully the up` per groupof reflectors, thel lower group will still be partly open. Assuming now that the pedal 21 isf further depressed, the rod 42 will slide through the bracket 44 thereby compressing the.` spring 48 without changing the position of the upper group of reflectors. The pedal 21 may then be still further depressed until the lower reflectors 39 have been fully closed.

When it is desired to reverse the action the pedal 21 is released and the leaf spring 27 retracts the mechanism and the lower group of reflectors 39 are opened, it being noted that the spring 48 expands and maintains the upper reflectors 52 closed, until the collar 47 comes into contact with the bracket 44 after which continued upward' movement of the pedal 21 will cause the upper group of reflectorsto be opened, the movement continuing until the mechanism has reached' its normal position, as shown in Figure 2.

In the modified form of the invention shown in Figures 5, 6 and 7, there is shown a grand piano including a casing 90, and including the sound producing mechanism and actions described and shown in connection with Figures 1 to 4 inclusive. A plurality of pedalsV shown three in number as at 91,v 92 and 93 is provided, these pedals being rotatablyv mounted in a pedal block 94 suspended below the piano casing by means of bars 95. A fourth pedal 96 is rotatably mounted on a lug 97 secured to the block 94. The rear end of the pedal 96 is operatively connected to the lower end of a vertical' reciprocating rod 98, the upper end of which is pivotally connected to one arm of a bell crank lever 100, mounted for rotation on a bracket 101 secured to the casing' 90, (see Figure 6). The other arm of the bell crank lever is pivotally connected by means of a linkv 102 to an arm 103, (see Figure 5). The arm 103 is fastened to avertical shaft 104. A collar 105 is secured to an intermediate portion of the link 102 and there is secured thereto one end of a spring 106, the other end of which is secured to a fixed portion of the casing 90. There is provided on the shaft 104 an arm 107 near the lower wall of the casing 90,

and the free end of the arm 107 is pivotally connected' by means of a link 108 to a collar 110 carried by a horizontal connecting rod 111. The rod 111 is pivotally connected at spaced points with a plurality of arms 112, each of which is mounted on one of the sound wave reflectors 113 forming collectively the lower group of sound wave reflectors as hereinbefore described with respect to the embodiment of Figures 1 to 4 inclusive.

A second arm 114 is fixed to the upper end of the shaft 104 and it has its outer end pivotally connect-ed' by means of a link 115 to a collar 117', (see Figure 7 The collar 117 is loosely mounted on a rod 118. Two additional collars 120 and 121 are mounted in fixed position on the rod118 in such a manner as to serve as abutments for the loose collar 117. A spring 122 is mounted upon the rod` 1.18 between one of the fixed collars 121 and the loose collar 117 so as to hold the loose collar normally against the other of the fixed collars 120. The rod 118 is pivotally connected at spaced points with a plurality of arms 123 each of which is mounted on one of the upper sound wave reflectors 124 forming collectively the upper group of sound wave reflectors similar to those described with respect to Figures 1 to 4 inclusive.

The shaft, 104 is also provided with an arm 133 affixed thereto, the free end of which is pivotally connected by meansvof a rod 134' to a collar 135 loosely mounted on a rod 136. Secured to this rod 136 are two spaced collars 137 and 138 each forming an abutment for the loose collar 135. A spring 140 is mounted on the rod 136 between the loose colla-r 135 and one of the fixed collars 1138, and normally maintains the loose collar 135 in contact'with lthe other of the fixed collars 137. The rod 136 is slidably mounted .in journal bearings 141 and 142 of conventional construction which are carried by the casing of the instrument.` The rod 136 is provided with a slotted member 143 arranged at an angle to the longitudinal inovenient of the rod 136, the slot of Which is engaged by a pin 144 mounted oii one end of an extensioiirod 145 which is slidably mounted injouinal beaiings`146 and 147 carried by. the casingfoif the instrument. Thustlie longitudinal movement of the rod 136 is communicated tothe rod 145, the rod Q145 being effectively an extensionA ofthe rod 135. d l For transmitting the longitudinal: motion of the rods 136aiid 145 thereis provided a plurality of links 150, pivotally connected to these rods and to al corresponding plurality of sound Wave reflectors 151.1 Theside Wall of the casing of the piano is opened by `niovement of these reflectorsI 151 to emit sound in a. horizontal direction. Each. of the reflec- .tors 151 is preferably -constructcd to conforni to thecurvature ot' the casing of the piano es-clearly shown in Figure 7 and is pivotallypiiiountcd as at 152 to rotate about ils longitudinal axis., Each reflector-isprov vided on its inner surface with. ajlayer of y sound reflecting material 4which may be .of sheet kinet-alsuch as sheet aluminum. Y

ln "theoperation of. the forinof the invention shown in kFigures 5, 6 and?, the

three pedals 91, 92 and 93 are operated by the foot and control the action ofthe piano v-in theusual manner. :llfheu it is desired to suppress the sound the auxiliary pedal v96 is depressed, thereby raising the rod 98, ro`

vtatingthc bell crank 100, pulling' Ithe rod 102 and turning the arm 103Which in turn rotates the shalt 104 in a clockwise direc- `Ation as seen iii-Figure 5.and in a counterclockirise direction as seen in Figure 6. This will causethe arm 107 to be rotated, thus moving the link 108to the right, which in turn will move the rod 111 to the right, thus moving the reflectors into closed position. d

The arm 1'14ivill also beiotated. thus moving the link 115 to the right which will j rod. 118 compressing the spring 122 untilv 1 will more the iod 145.

Y cause rthe rod 118 to be moved tothe-right,

thus closing the reflectors These are so adjusted that they Will close before thejlower set 113. As soon asthe reflectors V124 are closed, the collar 117 will slide along' the the lower set 113 has entirely closed.

, As the shaft104 rotates,vit will also turn thcaiin '133, which by means of a vlink 134' `Will'pull the rod 136 which at the saine time reflectors 151fto lie-closed, after Which the This will cause the` compressing' thev spring 140 until the lower sct'of reflectors113 have been entirely closed.

`i/Vhen the pressure of the footis gradually removed from the pedalV 96, the rod 10Q ,will

`be .moved to the right as seen in Figure 5 vThis will .first cause the reflectors .113 to be lidually opened and the collars 117 and -o5 will slide ralong' the rods 118 and 136 Auiililethey engage the collars 120 and'137` i'cspectiiiely, zitter which any 4further motion of the shalt 104 Will cause the reflectors 124 and 151 tobe gradually opened -at the'saine rate that the reflectors 113 are beingopened.

ln the modified torni 'of the invention shown in FiguresfS, 9and 10,-thesystem is applied lo a grand piano 160 Whicliis provided vwith the usual key ,boardx161 which `controls a standard action for striking vthe strings-such as has been described in connection with Figures 1 to 4;1The piano is provided with the usual pedal action 162` and also u'ithvan auxiliary pedal 163 which is mounted for rotation ina bracket 164 sefcured to the side of the regular'pedal action Iuredto a bracket `172 which is mounted upon thetranieavork of the piano.`l` The othereiid of the linkv168`ris pivoted ,to an arm 173 which is rigidlysecured to a shaft 174. Rigidly secured to the shaft 174 is an arm 175 to the end of which is pivoted a rod 176 Vwhich slides betweentwo rollers 177 `which are mountedin a bracket`178 which is rigidly secured to a bar 179. Thebar 179 `is formed of a material similar to that of the rods37of Fig.,2.: Secured to the rod 176 are tivo collars 181 and 182. A washer 183 is slidably mounted upon the rod 176 and is held against the bracket'178 by means of a spring 184. Pivoted to the bar 179 is a plurality of arms 185 which are mounted upon an equal number of reflectors 186 Which are mounted` for rotation about their longitudinal axes in the frame Work ofthe piano; A bracket 187 is provided against Which the bar 17 9 presses when the reflectors 186 are open. i

Rigidly secured to the upper end of the shaft 174 is an arm 190 to `which, is pivoted a rod 191 which slides betweenk two rollers 192, mounted in a bracket '193 which is secured to a bar 194. The liar117 9 is formed of a material similar to'tliat of the rod 37 spring' 171, the .other end `of which is se.

arel two collars y195 and 196. 'Slidably mountedv upon the rod 191 is a. washer 197 which is held against the bracket 193 by means of a spring 198. Pivoted to the rod 194 is a plurality of arms 199 which 'are mounted upon an equal number of reflectors 200, which are pivoted for rotation vabout their .longitudinal axes in the trame work ofthe piano. v

In the operation of the modified form of the invent-ion shown in Figures 8, 9, and 10 when the pedal 163 is depressed the rod 164 will be elevated, thereby rotating the bell crank 165 in a counter clockwise direction. This causes the link 168 to be moved to the right, thus rotating the arm 173, the sha-ft 174 and the twol arms A175 and 190-in a counter-clockwise direction as seen in Figure 9. This causes the two rods 176 and 191 to be moved to the right. The former merely slides through the bracket 178 until the collar 181 engages this bracket. The latter, however, causes the bracket 193 to be moved to the right through the action of' the collar 195 on the spring 198. This continues until the upper set of reflectors 200 have entirely closed, after which further motion of the rod 191 only produces a compression of the spring 198. The lower rod 176, however, as it continues to move to the right, after the collar 181 has engaged the bracket 178, will causethe lower set of reflectors 186 to be closed. n

lWhen the pressure on the pedal 163 is gradually released, vthe reverse action will take place under the action of the spring 171, thus causing the rods 176 and 191 to be moved to the left. During the first half of the motion, the lower reflectors will be opened, due to the spring 184 pressing against the bracket 178 until the bar 179 comes up against the bracket 187. During this interval, theupper reflectors 200 will remain closed` until the collar `196 engages the bracket 193. During the second half of the motion of these rods, the lower reflectors 186 will remain open and the spring 184 will be compressed while the upper reflectors 200 f'will be opened, due to the colla-r 196 pressing against the bracket- 193 until at the end of 'the motion, both sets of reflectors are fully open. It will be seen from this description of' the operation of the `structure shown in Figures 8 to 10, thatwhen the pedal is depressed it will causerst the top set of reflectors to be gradually closed, and after `they are entirely closed, the bottom set will be gradually closed. When the pressure on the pedal is graduallyreleased the opposite action, takes place and the lower setpof reflectors will graduallyopen tof their full extent whilerthe upper set remains closed, after vwhich the yupper set is gradually opened.

In the modified form shown in Figure 11,

the rod 191 is threaded and is provided with a split nut 201. The bracket 193 is provided with a pointer 202 which indicates on a scale 203 which is mounted on two arms 204 and 205, which are rigidly secured to the rod 191. In this way the point at which the reflectors 200 will close with respect to the motion of the foot pedal and also with respect to the closing of the lower reflectors, can be regulated by adjusting the position ofthe nut 201. A similar device may be provided on the lower reflecting mechanism so that its opening may be controlled in a. similar manner by properly adjusting these nuts.

By means of the mechanism shown in the accompanying figures, the volume of sound emitted by the upper and lower set of reflectors can be so controlled as to produce varying efl'ects as shown in Figures 12, 13 and 14. It has been found by experiment, that the ratio ol sound emitted from the bottom and top of a piano is in the proportion of 6 to 8, that is, the volume of sound emitted from below is three-quarters of that emitted from above.

Figure 12 shows diagrammatically the control of the volume of sound emitted from the piano described in connection with Figures 1 and ln this figure, the abcissa represents the mot-ion of the foot pedal and the ordinates, the corresponding volume of sound emitted. 'The line 210 represents the volume of sound emitted by the lower reflectors 39 and the line 211, the volume of sound emit-ted by the upper reflectors 52. rlhis line reaches its zero intensity at the time the upper reflectors are completely closed and while the lower reflectors are still partly open, as described in connection with Figures 1 and 2. The line 212 shows the total volume of sound emitted by both upper and lower reflectors. It will be seen from the shape of the curve 212 that the tone shading is more sensitive as the volume of sound emitted reaches its lower limits, which is found to produce betterelfects as this seems to be the most important part of the curve for producing finer tonal nuances. The upper part of the line 212 is steeper where the variation of the volume of sound emitted has less tonal effect.

In Figure 13 is indicated the variation of the volume of tone emitted by the piano described in connection with Figures 8 and 9, in which the upper set of reflectors 200 are entirely closed before the lower set of reflectors 186 start to close. In this figure the lines 215 and 216 indicate the way in which the volume of sound emitted by the upper and lower reflectors varies, and the line 217 indicates the way in which the total volume of sound emitted by the piano varies. It will be seen :from this figure that the extent over which the sound variation is produced ill) has been greatly lengthened so as to pro- In Figure 14 is shown the variation in the; yvolumeof sound emitted by the piano described in connection with Figures 8 and 9, when the adjusting device shown in Figuie 11 is applied to both the upper'and lower mechanisms. ln this case, the devices are so adjusted that'the lower reflectors 186 ywill start to close when the upper reflectors 200iare Vhalf closed, and the upper reflectors 20() will be entirely closed when the lower reflectors 186 are half closed. The rat'e'at which the' lvolume of' sound emitted by the upper and lower` reflectors varies is indicated by the lines 220 and 221, and the rate at which Vthe total volume ofsound emitted by the piano is indicated by thejline 222. It will be seen from this curve that the volume of sound emitted drops off slowly at first, then more abruptly, during the middle part of the motion of the pedal, and then more slowly again toward the end. 'By

.suitable adjustment, the mechanism shown in Figure 11,. other desired variations of tone shading may be obtained.

f The invent-ion upon which this application is based is broader than the specific einbodiment'shown and describedfor the purposeof illustratingat least one of the ways in` whicli'it may be employed. The scope vof the invention is therefore to be understood as not being limited by the present specific description. I intend yno limitations other than those imposed by the claims. i i

`VVhat is claimed is 1. A modulating system for a pianoforte, comprising a plurality of resonating chainbers, a plurality of sound wave reflectors arranged in groups for variably controlling the'volume of sound emitted from the different resonating chambers independently,

. a. tone modulating pedal, means operatively ly, means operatively connecting said device'with one of the groups of reflectors, and means including a. yielding element operatively interconnecting'said device and the'remaining groups of reflectors for operating the reflectors in groups successively.

for variably controlling the sound emitted from'the pianoforte in different directionsk and arranged in groups, an operatingarm for each group of-i'eliectors, a control device for said reflectors, and connecting means including a yielding element operativelyj interconnected between the control device and said operating arms.

4. A musical vinstrument including avibratory sound producing element, a casing therefor having controllable apertures arranged in groups for controlling the emission of sound from said element in different c. A' modulating system for a pianoforte" comprising a group of sound wave reflectorsdirections, a plurality of centrally pivoted.V

operating device with the remainingfones of said connecting rods.

5. A musical instrument comprising a vibratory source of musical tone, a resonant element adjacent thereto for reflecting and for transmitting sound, a plurality of sound wave reflectors arranged in groups to control the, reflected and the transmitted sound respectively, means for operating each group of reflectors independently of the remaining groups, a control pedal, a motion transmitting element connecting said control pedal with the operatiii means of onev group ofi-eflectors, and ad itional motion transmitting devices, each including a yielding element, linterconnecting said lpedal with 6.I A musical instrument including a vibratory sound producing element, a casing therefor having controllable aperturesY arranged in groups for-controlling the emission ofsound from said element in different directions, a plurality of centrally pivoted rotatable sound wave reflectors positioned in said apertures, for variably closing said apertures andarranged in groups, a' connecting rod interconnecting the reflectors of each group, a single device vfor rotating allof said. reflectors, means for directly connecting said device with one of said connecting rods, means including a-yielding .element operatively interconnecting said` operating device with the remaining ones of said conthe others of said operating means respecnecting rods, and means for modifying the action-of said'last named interconnecting means. Y l

7.- A. musical instrument including a viice bratory sound producing element, a casing therefor having controllable apertures ar-v ranged in groups for controlling the emission of sound from said element in different directions, a plurality of centrally pivoted rotatable sound wave reflectors positioned in said apertures, for variably closing said apertures and arranged in groups, a connecting rod interconnecting the reflectors of each group, a single device for rotating all of said reflectors, means for directly connecting said device with one of said connecting rods, means including a yielding ele-V 'tioned in said apertures, for variably closing said apertures and arranged in groups, a connecting rod interconnecting the reflectors of each group, a single device for rotating all of said reflectors, a connecting device interposed directly between said device and one of said connecting rods, a connecting de- ;vice including a yielding element operatively interconnecting said operating pedal with the remaining ones of said connecting rods,'

and an adjustment nut for varying the action of at least one of said connecting devices.

9. A musical instrument comprising a vibrating string, a hammer for vib ating said string by percussion, a sounding board adjacent the string for reflecting and for transmitting sound, a casing therefor, a plurality of sound wave reflectors in the walls of the `.casing and arranged in groups to control the reflected and the transmitted sound respec-v tively, connecting links interconnecting the reflectors of each group independently of the remaining group, a control pedal, a motion transmitting device connecting said control edal with the connecting link of one group 'of reflectors, and an additional motion transmitting device, each including a yielding eleinent, interconnecting said pedal with the others of said connecting links respectively.

. 10. A modulating system for a pianoforte comprising a plurality of resonating chamber-s, a plurality of sound wave reflectors arranged in groups for variably controlling the volume of sound emitted from the different resonating chambers independently, a tone modulating pedal, and means controlled by said pedal for successively operating the groups of reflectors, in groups.

11. A modulating system for a pianoforte comprising a plurality of resonating chambers, a plurality of sound wave reflectors for each of said chambers for variably controlling the volume of sound emitted from the respective chambers independently, a tone modulating pedal, and means controlled by said pedal for operating said groups of reflectors successively.

l2. In a musical instrument, the combination with a piano of a casing having sound openings, a plurality of normally open cen- `trally pivoted closures for said openings,

means controlled entirely at the will of an operator for variably closing said closures to control the intensity of sustained notes emitted, means interconnect-ing said controlled means, and certain ones of said closures, and means including a lost motion device interconnecting said controlled means and the remainder of said closures.

13. A modulating system for a pianoforte comprising a plurality of resonating chambers, a plurality ofsound wave reflectors arranged in groups for variably controlling the volume of sound emitted from the different resonating chamber-s independent-ly, a tone modulating pedal, and means including a compression spring controlled by said pedal for successively operating the groups of reflectors, in groups.

14. A modulating system for a pianoforte comprising a plurality of resonating chambers, a plurality of sound wave reflectors for each of said chambers for variably cont-rolling the volume of sound emitted from the respective chambers independently, a tone modulating pedal, and means including a compression spring controlled by said pedal for operating one of said groups of reflectors after the remaining groups.

Signed at New York in the county of New York and State of New York this 16th day of November A. D. 1925.

JOHN HAYS HAMMOND, JR. 

